Manual or automatic means for correcting time-keeping mechanisms



Jan. 5, 1937. R MCDONALD 2,066,357

MANUAL OR AUTOMATIC MEANS FOR CORRECTING TIME KEEPING MECHANISMS Filed Nov. 12, 1934 2 Sheets-Sheet l INVENTOR. GEORGE R Mc 001m 1.0

' [BIZ/WW.

ATTORNEYS.

Jan.5, 1937. G R MCDONALD 7 2,066,357

MANUAL OR AUTOMATIC MEANS FOR CORRECTING TIME KEEPING MECHANISMS -.Filed- Nov. 12, 1934 2 Sheets-Sheet 2 6 2s- 8 7 3 33 a, 38 fi 4o 9 37 II as J- 31 J4 43 32 42 I 44 30 I 29 I 45 2 49 4? a 24 1 5,, m T I H I 46 A I 22 19 1 1 15 FF 4/ 'fiT I I I 2 ll I I {9 I 1 I I ,l I '1 1 7. 5 II I IE-M 'llllf Hlllllllllllllllllllll z 5 INVENTOR.

GEORGE E. Mc Do/vA L 0 ATTORNEYS.

Patented Jan. 5, 1937 UNITED STATES PATENT OFFICE MANUAL OR AUTOMATIC MEANS FOR COR,-

RECTING TIME-KEEPING MECHANISMS 8 Claims.

My invention relates to improvements in manual or automatic means for correcting time-keeping mechanisms, and it consists of the combina tions, constructions and arrangements hereinafter described and claimed.

An object of my invention is to provide manual or automatic means for correcting time-keeping mechanisms which can be inserted between the source of power and the time-keeping indicating hands. The means continuously corrects the time-keeping mechanism so that at any par ticular instant the correct time is given.

In many timepieces the amount of gain or loss is known, and when this means is applied to such a mechanism the gain or loss can be automatically compensated for, so that the timepiece will actually keep correct time. The means can be actuated by the clock mechanism or can be manually actuated, and in the latter case accurate adjustment can be manually made.

The device is designed primarily to be used in electric clocks in which a synchronous motor drives the clock mechanism where the motor is actuated by a source of alternating current wherein the frequency of pulsations is in even multiples of the solar second of time, in such a manner that the units of time according to the sidereal system will be indicated. Translation gears are interposed between the motor and the clock mechanism for causing the clock mechanism to keep sidereal time, and these gears are caused to move faster or slower for correcting purposes. In my co-pending application, Serial Number 752,770, filed Nov. 12, 1934, I Show an electric clock with the translating mechanism included therein.

In the present case I also show an electric clock with a translating mechanism to change the time from solar to sidereal, and I further include the means for correcting the sidereal time. The translating gears will cause the clock mechanism to gain .0006633 sidereal days in one year. This equals 57.28 seconds in the course of a year. The compensating device causes the entire translating mechanism to correct itself to within onehalf second of error instead of 57 .28 seconds in a years time. The error of one-half second may be corrected by manual means at the end of the year.

Other objects and advantages will appear in the following specification, and the novel features of the device will be particularly pointed out in the appended claims.

My invention is illustrated in the accompanying drawings forming a part of this application, in which Figure 1 is a front elevation of a clock for keeping sidereal time;

Figure 2 is a section along the line 22 of Figure 3;

Figure 3 is a diagrammatic view of the clock mechanism, the translating gearing, and automatic compensating means;

Figure 4 is a section along the line 4-4 of Figure 3; and

Figure 5 is a section along the line 5-5 of Figure 4.

In carrying out my invention I provide a clock for keeping sidereal time, and this clock comprises a standard I on which a frame 2, see Figure 3, is mounted. This frame carries a dial 3, and the dial has an outer circular row of marks 4 for indicating seconds, and an inner circular row of marks 5 for indicating hours. The dial face shows twenty-four hours instead of the customary twelve hours.

I further show in Figure 1 an indicator hand 6, a sweep second-hand 1, a minute-hand 8, and an hour-hand 9. All of these hands are operatively connected to an electric synchronous motor l shown in Figure 3, and the connection is made in the following manner.

The electric motor l0 rotates a shaft H, see Figures 3 and 5, and this shaft carries a pinion l2. The pinion l2 meshes with a planetary gear l3, and this latter gear rotates a planetary gear l4 because the gear I4 is mounted on the same shaft l as the gear l3. The gear I4 forms one of the gears in the translation train which consists of the additional planetary gears l6 and I1,

' and the gear I8.

The translation gear M has sixty-one teeth, and meshes with the gear 16 which has seventythree teeth. The gear 16 is mounted on a shaft l9, and the gear I! is mounted on the same shaft. The gear IT has sixty teeth and meshes with the gear l8 which has fifty teeth. The shafts l5 and I9 are carried by a gear 20, and the purpose of the gear 20 will be hereinafter described.

Figure 5 shows the gear 29 as being provided with a recess 2|, and the gear I8 is mounted in this recess. The cylindrical wall 22 of the recess has an opening 23 therein through which a portion of the gear 18 extends. It is this portion of the gear l8 that meshes with the gear H.

The gear I8 is rigidly mounted on a sleeve 24 and the sleeve is rotatably mounted on a shaft 25. Figure 5 shows the shaft 25 keyed to the hub 26 of the gear 20, and further shows the hub 26 as having a central bore 21 for receiving the reduced end 28 of the shaft II. It will be seen from this construction that the rotation of the shaft I I in one direction will cause a rotation of the sleeve 24 in the opposite direction, and at the speed which will equal one sidereal second for each of the spaces included between the marks 4 which it traverses at a uniform rate. Figure 3 shows the sleeve 24 as carrying the sweep second-hand I.

The connection between the minute-hand and the second-hand is shown in Figure 3, and this comprises a pinion 29 rigidly secured to the sleeve 24 and meshing with a gear 30. The gear 30 has an integral gear 3| secured thereto, and the gear SI meshes with the gear .32. The gear 32 has a sleeve 33 rotatably mounted on the sleeve 24 and the sleeve 33 carries the minutehand 8. The gearing is such between the secondhand and the minute-hand that the second-hand will take sixty revolutions to move the minutehand through one revolution.

Figure 3 also shows the connection between the hour-hand and the minute-hand, and this includes a gear 34 which is integral with the sleeve 33, and which meshes with a gear 35. This gear 35 has the pinion 36 rotating at the same speed, and the pinion meshes with the gear 31 which has an integral sleeve 38 rotatably mounted on the sleeve 33. The sleeve 38 carries the hourhand 9. The gearing between the minute-hand and the hour-hand will cause the hour-hand to make one revolution for each twenty-four revolutions of the minute-hand.

The rod 25 extends through the sleeve 24, and Figure 3 shows the indicator hand 6 mounted on the rod 25.

The operation of the device thus far described will cause the synchronous electric motor I to rotate the hands 1, 8 and 9 to indicate sidereal time. As stated in the companion case there are 366.2421 sidereal days a year, and there are 365.2421 solar days in the same year. This gives a ratio of 1.00273791. The translating gears I4, I6, I'. and I8 will give a ratio of 1.0027397260. The ratio obtained by the gears is 1.0027397260 where gears having this ratio are introduced into the clock mechanism which normally causes the hour-hand to make one revolution of the clock dial in twenty-four solar hours. The additional gearing causes the hour-hand to move at an increased rate, such that in 365.2421 solar days the hour-hand will make 366.242'76 revolutions of the clock dial. The difference between this number and the true number of sidereal days occurring in this period of time is .0006633. The clock mechanism would therefore gain in the course of a year .0006633 sidereal days. This equals 57.28 seconds. In order to correct this error I provide the gear 20, and the mechanism now to be described.

Again referring to Figure 3 it will be noted that I provide means controlled by the clock for operating the gear 20. This means includes a gear 39 that meshes with a pinion 40 that is integral with the gear 31. The gear 39 rotates a shaft 4| which is loosely mounted in the pinion 35 and which carries a pinion 42. The pinion 42 meshes with a gear 43 and this gear is connected by a friction clutch 44 with a shaft 45. The shaft 45 carries a pinion 46 which meshes with the gear 20.

The movement of the parts 40 to 46 inclusive is such as to move the gear 20 in a direction opposite to the direction of rotation of the sleeve 24. The rotation of the large gear 20 having mounted upon it the planetary system consisting of the gears I3, I4, I6, and I! will impart to the second-hand l rotation additional to that furnished by the driving motor by utilizing the property of the planetary gears. By a proper selection of the relative diameters of the driving pinion I I, and its axially mounted driven gear I8, I am able to cause the second-hand I to make one complete revolution in a reverse direction when gear 20 and its planetary train makes one revolution. In the case illustrated, the clock runs fast 57.28 seconds in one year. If the relative diameters of pinion II and gear I8 be chosen as stated, in one year the large gear 20 will turn back of one revolution, thus causing the clock at the end of the year to give its time indication with a minimum of error.

If it is desired to manually correct the timepiece it can be done by manually rotating the shaft 4'! by means of a knob 48, and this shaft 41 will rotate the beveled gear 49 which meshes with a beveled gear 50, and which is mounted on the shaft 45. The rotation of the gear 50 will rotate the shaft 45 and the friction clutch 44 will permit relative rotation between the shaft 45 and the gear 43. The manual rotation of the shaft 45 will manually rotate the gear 20 into the desired position. After the manual adjustment has been made the shaft 45 will be rotated by the gear 43, through the clutch 44.

Since the gear 20 does not rotate through a complete revolution in the course of an entire year, it will be seen that the movement is practically imperceptible. This movement is indicated by the indicator hand 6 which is directly connected to the gear by the shaft 25. which is keyed to the gear 20 in the manner shown in Figure 5. The correction of time is continuous, that is the gear 20 will be slowly revolved in a direction opposite to the rotation of the sleeve 24, and at the end of the year the gear will have taken almost one complete revolution opposite to the sleeve 24. The gear 20, in its rotation, will carry with it the shafts I and I9, and therefore the translation gears will always be in mesh with the pinion I2 and will continuously drive the sleeve 24.

From the foregoing description of the various parts of the device, the operation thereof may be readily understood.

The synchronous motor I0 through the clock mechanism and through the translation gears I 4, I6, I1 and I8 will cause the hands 1, 8 and 9 to indicate sidereal time. The translation gears cause the clock to gain .0006633 sidereal days in the course of a year.

This error is practically corrected by mounting the translation gears on the large gear 20 and causing the clock mechanism to rotate this large gear backward through almost a complete revolution in the course of a year. The backward rotation of the large gear is shown by the indicator hand 6. The correction thus provided is continuous throughout the year and the error is reduced from 57.28 seconds to one-half second. This small error may be corrected manually by turning the knob 48 if desired.

It will be seen, therefore, that the resultant motion of the hand 1 due to the planetary gears, is less than that which would be imparted to the hand I if only straight gearing alone were employed. Correction is thus made for the excess motion of the hand 1 by the clock mechanism itself and the correction is continuously made throughout the year.

While I have shown only the preferred form of my invention, it should. be understood that various changes or modifications may be made within the scope of the appended claims without departing from the spirit of the invention.

I claim:

1. The combination with a clock mechanism having time indicating hands, means for moving the mechanism for causing the hands to keep substantially accurate time, a driving member and a driven member for actuating the hand moving means, of a time correcting mechanism including a gear driven by the hand moving means in a direction to correct the movement of the hand moving means, said hand moving means including a gear on the driven member concentric with the first named gear, and said time correcting mechanism also including a gear on the driving member concentric with the first named gear, and planetary gearing carried by the first named gear and meshing with the gears on the driving and driven members.

2. A clock correcting mechanism including a driven gear for actuating the clock mechanism for keeping practically correct time, a driving gear axially aligned with the driven gear, a third gear axially aligned with said driving and driven gears, planetary gearing carried by the third gear and meshing with the driving and driven gears for transmitting motion therebetween, and means for rotating said third gear in the desired direction for correcting the time.

3. A clock correcting mechanism including a driven gear for actuating the clock mechanism for keeping practically correct time, a driving gear axially aligned with the driven gear, a third gear axially aligned with said driving and driven gears, planetary gearing carried by the third gear and meshing with the driving and driven gears for transmitting motion therebetween, and means for rotating said third gear in the desired direction for correcting the time, said means being operatively connected to the driven gear.

4. The combination with an electric clock having a synchronous motor wherein the frequency of the current is in even multiples of the solar second of time, said motor having a driving gear, time keeping hands, and a clock mechanism for actuating the hands, of a driven gear axially aligned with the driving gear, a third gear axially aligned with the other two gears, planetary gearing carried by the third gear and meshing with the other two for indicating nearly but not quite correctly, sidereal time instead of solar time, a time correcting mechanism, including the third gear, and means for rotating said third gear in the desired direction for correcting the time except for a very small yearly error.

5, The combination with an electric clock having a synchronous motor wherein the frequency of the current is in even multiples of the solar second of time, said motor having a driving gear, time keeping hands, and a clock mechanism for actuating the hands, of a driven gear axially aligned with the driving gear, a third gear axially aligned with the other two gears, planetary gearing carried by the third gear and meshing with the other two for indicating nearly but not quite correctly, sidereal time instead of solar time, a time correcting mechanism, including the third gear, and means for rotating said third gear in the desired direction for correcting the time except for a very small yearly error, said means being operatively connected to the driven gear.

6. In combination, a synchronous motor wherein the frequency of the current is in even multiples of the solar second of time, a clock mechanism geared to keep solar time when actuated by the motor, a gear translating mechanism interposed between the motor and the clock mechanism for causing the latter to indicate nearly but not quite correctly sidereal time, and means for continuously correcting the gear translating mechanism for indicating correct sidereal time except for a very small yearly error.

'7. In combination, a synchronous motor wherein the frequency of the current is in even multiples of the solar second of time, a clock mechanism geared to keep solar time when actuated by the motor, a gear translating mechanism interposed between the motor and the clock mechanism for causing the latter to indicate nearly but not quite correctly sidereal time, and means for continuously correcting the gear translating mechanism for indicating correct sidereal time except for a very small yearly error, said correcting means being actuated by the clock mechanism.

8. The combination with an electric clock having a synchronous motor, wherein the frequency of the current is in even multiples of the solar second of time, time indicating hands, and a clock gearing mechanism connected with the hands, of a gear translating mechanism interposed between the clock gearing mechanism and the motor for causing the clock mechanism to move the hands for indicating nearly, but not quite correctly, sidereal time, and means actuated by the clock gearing mechanism for continuously correcting the gear translating mechanism for causing accurate sidereal time to be given at all times except for a very small yearly error.

GEORGE R. MCDONALD. 

